Fixed issue 1441. Forced check that value was of an appropriate type. #1442
I verified that the issue reported was a difference between MRI and JRuby. Looking at the RubyBigDecimal class it seems to be a fairly simple fix, changing a false to true. After making this change to the "-" method code, I rebuilt JRuby and tried the example again.
This change seems to address the issue. Please let me know if there is something else that I have missed.